1. Field of the Invention
The present invention is related to a projection device, and particularly to a lens array and an illumination module using the same.
2. Description of Related Art
FIG. 1 is a schematic view of a conventional illumination module. Referring to FIG. 1, an illumination module 100 includes a light source 110, a first lens array 120, a second lens array 130 and a polarization converting system 140. The light source 110 emits an illuminating beam L10, and the first lens array 120 and the second lens array 130 are sequentially disposed on an optical path of the illuminating beam L10. The first lens array 120 and the second lens array 130 uniformize the illuminating beam L10. The polarization converting system 140 is disposed on the optical path of the illuminating beam L10 from the second lens array 130 and renders the illuminating beam L10 as a polarized polarization beam L120.
The polarization converting system 140 has a plurality of absorption devices 142, a plurality of polarization beam splitters 144, a plurality of reflection devices 146 and a plurality of half-wave plates 148. The illuminating beam L10 enters the polarization beam splitter 144, and a portion of the illuminating beam L10 penetrates the polarization beam splitter 144 and the half-wave plate 148. Another portion of the illuminating beam L10 is reflected by the polarization beam splitter 144 to the reflection device 146 and then reflected by the reflection device 146 to pass through the polarization converting system 140.
The absorption device 142, the polarization beam splitter 144, the reflection device 146 and the half-wave plate 148 are symmetrically disposed opposite to a reference plane 140a. The first lens array 120 and the second lens array 130 have a plurality of first lenses 122 and a plurality of second lenses 132 respectively. Each of the first lenses 122 and each of the second lenses 132 correspond to a central point of each polarization beam splitter 144 respectively. Since the polarization converting system 140 is symmetrically disposed, two adjacent symmetric polarization beam splitters 144a are disposed at two sides of the reference plane 140a. To coordinate with two adjacent polarization beam splitters 144a so that a first lens 122a and a second lens 132a both align with a central point of the polarization beam splitter 144a. A width d′ of the first lens 122a and the second lens 132a corresponding to the polarization beam splitter 144a is smaller than a width d of the first lens 122 and the second lens 132. Thus, the illuminating beam L10 passing through the first lens array 120 and the second lens array 130 is rendered inconsecutive.